With the trend toward high-power lithium ion batteries having high energy density, studies have focused on using metal materials alloyable with lithium, such as silicon, germanium, tin, and zinc, and oxides of these metals as a negative electrode active material instead of carbonaceous materials such as graphite.
PTL 1 described below proposes a negative electrode for non-aqueous electrolyte secondary batteries that contains, as a negative electrode active material, a graphite carbon material and a composite of a carbon material and a material containing Si and O as constituent elements.